Problem with reference design of FmcommS3

I try to work with example 'qpsktxrx.xls' (simulink) on kit FmcommS3 but i met several problems. Please give me some advices.

1. when i try to demodulate received signal to bits and compare it with the original bits (sending) then result doesnt match.

2. I dont really understand why the transmitter work with 60000 samples/frame (inputchannel/2), and the receiver work with 40000 samples/frame (but sample time is same and = 1/245760*outputchannel), i think if its sample time is same then its frame rate much be diffirent ?

3. In the block selector of receiver, index vector is selected at [1:4000] ? did they just execute downsampling or something?

1. The QPSK tx and rx example we provide is a simplified version of MathWorks example (QPSK Transmitter and Receiver - MATLAB & Simulink Example). If you would want to see rx bits match tx bits, you need to implement Frame Synchronizer and etc. based on our example. The MathWorks example is a good reference.

2. Since the libiio interface works in a buffer mode, the actual frame rate is not that important in our example. We specify an input channel size larger than an output channel size to make sure there is always enough data for receiver to work with, so that the constellation makes sense.

3. index vector is not doing downsampling here. It just selects the portion of the signal that QPSK receiver will work on.

1. The QPSK tx and rx example we provide is a simplified version of MathWorks example (QPSK Transmitter and Receiver - MATLAB & Simulink Example). If you would want to see rx bits match tx bits, you need to implement Frame Synchronizer and etc. based on our example. The MathWorks example is a good reference.

2. Since the libiio interface works in a buffer mode, the actual frame rate is not that important in our example. We specify an input channel size larger than an output channel size to make sure there is always enough data for receiver to work with, so that the constellation makes sense.

3. index vector is not doing downsampling here. It just selects the portion of the signal that QPSK receiver will work on.